This invention relates to surveillance systems and, in particular, to a movable surveillance camera capable of utilizing fast Ethernet signals in a video surveillance system.
Surveillance systems often include movable cameras, which are referred to in the industry as pan/tilt/zoom cameras or PTZ cameras. The PTZ cameras employ circuitry and drive mechanisms for panning, tilting, and zooming the camera. A surveillance camera assembly with 360 degree pan motion requires a rotational joint that can conduct electrical power and signals between the camera on the rotating structure and the electronics on the stationary structure. Typical designs use a slip ring to realize this power/signal rotational joint. Such slip rings have generally been used in movable analog camera assemblies to transmit the analog video signals across the slip ring. With the inclusion of higher resolution cameras, such as high-definition cameras, and Ethernet signals in particular, fast Ethernet signals, such as 100BASE-T, there has arisen a need for a surveillance camera configuration that allows the use of higher resolution cameras in PTZ domes with 360 degree panning. When prior art movable cameras employing slip rings attempt to use high definition cameras and fast Ethernet signals, they generally suffer from increased bit errors, crosstalk, and even total loss of signal. Accordingly, an improved camera assembly is necessary to meet the high quality and reliability requirements of modern video surveillance systems.